The master ruler for Half Square Triangles! Bloc Loc's patented technology channel is machined with a 1/8" clear acrylic channel which locks the seam allowance in place and allows the quilter to square up a half-square triangle block in just seconds with ultimate accuracy and safety.
No turntable is necessary, just turn the ruler and your fabric moves with Bloc Loc!!! No more "ruler rock" or slipping guaranteed!! Bloc Loc rulers have easy to read solid markings throughout every 1/2" and perimeter markings to 1/8".
Instructions for using the rulers can be found here.